For many years mobile (portable) electric power plants have been utilized, for example, in association with motor vehicles to locally generate electric power and particularly to provide a portable source of 120 volt alternating current. Such power plants typically must be accommodated in a relatively small compartment provided for this purpose. The size of the compartment is dictated both by space and noise considerations. At the same time, a countervailing consideration is the fire hazard and burn hazard associated with the operation of these units.
The internal combustion engine, typically a gasoline, single cylinder four stroke engine, produces exhaust gas temperatures in excess of 665.degree. C. Such temperatures are sufficient to ignite certain combustible materials and are sufficiently high to injure any person coming in direct contact with the exhaust manifolds, through which such gases pass. Merely enclosing the exhaust manifold to prevent direct contact by an operator or by combustible materials with the exhaust manifold does not substantially reduce the problem. The relatively limited circulation of air within such a single hull enclosure transmits most of the heat to the enclosure so that the enclosure itself attains unacceptably high temperatures.
The high heats produced in the power plant compartment also produce a severe environment for the on-board electronics. Relatively high power dissipation electronics must be provided to regulate the power produced and to govern the charging of any associated starting batteries. The performance, service life and reliability of the associated on-board electronic components such as high power rectifiers, are adversely affected by the resulting temperatures.
Accordingly, it is desirable to have a cooling system for mobile electric power plant enclosures. To reduce the temperatures associated with both the exhaust system enclosure and the electronic enclosures, and thereby reduce the risk of fire hazard and burn hazard. Such a system is particularly desirable where it does not substantially increase the cost of the enclosure and further muffles the sound from the operating power plant.